Call map_file() with its new args, including a suggested window

size.

checksum.c

@@ -102,7 +102,7 @@ void file_checksum(char *fname,char *sum,OFF_T size)
 	if (fd == -1)
 		return;
 
-	buf = map_file(fd, size, CSUM_CHUNK);
+	buf = map_file(fd, size, CSUM_CHUNK * 2048, 0);
 
 	mdfour_begin(&m);
 

generator.c

@@ -154,7 +154,7 @@ static void sum_sizes_sqroot(struct sum_struct *sum, uint64 len)
 			c >>= 1;
 		} while (c >= 8);	/* round to multiple of 8 */
 		blength = MAX(blength, BLOCK_SIZE);
-		blength = MIN(blength, MAX_MAP_SIZE);
+		blength = MIN(blength, MAX_BLOCK_SIZE);
 	}
 
 	if (protocol_version < 27) {
@@ -209,7 +209,7 @@ static void generate_and_send_sums(int fd, OFF_T len, int f_out)
 	sum_sizes_sqroot(&sum, len);
 
 	if (len > 0)
-		mapbuf = map_file(fd, len, sum.blength);
+		mapbuf = map_file(fd, len, MAX_MAP_SIZE, sum.blength);
 	else
 		mapbuf = NULL;
 

receiver.c

@@ -222,7 +222,8 @@ static int receive_data(int f_in, char *fname_r, int fd_r, OFF_T size_r,
 	read_sum_head(f_in, &sum);
 
 	if (fd_r >= 0 && size_r > 0) {
-		mapbuf = map_file(fd_r, size_r, sum.blength);
+		OFF_T map_size = MAX(sum.blength * 2, 16*1024);
+		mapbuf = map_file(fd_r, size_r, map_size, sum.blength);
 		if (verbose > 2) {
 			rprintf(FINFO, "recv mapped %s of size %.0f\n",
 				safe_fname(fname_r), (double)size_r);

sender.c

@@ -208,7 +208,11 @@ void send_files(struct file_list *flist, int f_out, int f_in)
 			return;
 		}
 
-		mbuf = st.st_size ? map_file(fd, st.st_size, s->blength) : NULL;
+		if (st.st_size) {
+			OFF_T map_size = MAX(s->blength * 3, MAX_MAP_SIZE);
+			mbuf = map_file(fd, st.st_size, map_size, s->blength);
+		} else
+			mbuf = NULL;
 
 		if (verbose > 2) {
 			rprintf(FINFO, "send_files mapped %s of size %.0f\n",